Trimethylolpropane ester-based plasticizer composition for polyvinyl chloride resin

ABSTRACT

The present invention relates to a trimethylolpropane ester-based plasticizer composition for polyvinyl chloride resin, more particularly a plasticizer composition comprising trimethylolpropane ester capable of using as plasticizer of polyvinyl chloride resin. The present invention can prepare polyvinyl chloride resin having superior tensile strength, elongation, migration, and sheet heating loss etc. by using the plasticizer composition.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/KR01/02127 which has an Internationalfiling date of Dec. 7, 2001, which designated the United States ofAmerica, and which claims priority to Korean Application 2001-00006555,filed Jan. 5, 2001 under 35 U.S.C. §119.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a trimethylolpropane ester-basedplasticizer composition, and more particularly to a trimethylolpropaneester-based plasticizer composition used as a plasticizer when preparingpolyvinyl chloride resin.

(b) Description of the Related Art

Polyvinyl chloride (PVC) is a general resin that can attain variousphysical processing properties by suitably mixing additives such asstabilizers, fillers, pigments, and plasticizers. Polyvinyl chloridewith the various physical processing properties is widely used as amaterial for goods such as wallpaper, gloves, and toys, as well as forpipe, electric wire insulation, and artificial leather. The plasticizeris an essential additive for preparation of polyvinyl chloride resin, toimpart various physical properties such as processability, flexibility,electric insulating ability, etc.

The representative plasticizers used in processing of polyvinyl chlorideresin include phthalate-based plasticizers, adipate-based plasticizers,and trimellitate-based plasticizers, etc. The most generally usedplasticizer, di-2-ethylhexylphthalate (DEHP), is phthalate-based, and itplays a role as a standard plasticizer for performance evaluation ofother plasticizers.

On the other hand, trimethylolpropane ester is mainly a well-misciblelubricant for refrigerants, (U.S. Pat. No. 5,470,497), and it is alsoused as an additive for lubricating oil in automobile engines (U.S. Pat.No. 4,061,581). Furthermore, trimethylolpropane ester can effectivelyremove precipitation materials from metal surfaces in engine parts ofautomobiles (Japanese Patent Laid-open Publication No. Heisei 5093191A2), and an ester prepared by synthesis of trimethylolpropane and fattyacids improves friction resistance of a road surface without reductionof friction resistance of a wet road (Japanese Patent Laid-openPublication No. Heisei 1113444 A2).

Although the trimethylolpropane ester is used as an additive forlubrication as mentioned above, it has structurally weak physicalproperties compared with phthalate-based and trimellitate-basedplasticizers widely used in the related art, and thus it is not used asa plasticizer when processing polyvinyl chloride.

For example, as a plasticizer used in processing of polyvinyl chlorideresin, trimethylolpropane ester comprises mono-component esters eachsynthesized by adding hexane or 2-ethylhexanoic acid as an acid of analiphatic group series, or benzoic acid as an acid of an aromatic groupseries, to trimethylolpropane as a triply-charged alcohol.

In addition, triethanolmethane ester is a plasticizer having physicalproperties superior to trimethylolpropane ester or other plasticizers.The trimethylolpropane ester was inferior in physical properties, asmentioned, as the ester of the mono component has too many weak bonds toplay a role as a plasticizer, even in the case when compatibility withpolyvinyl chloride resin does not exist (U.S. Pat. No. 3,939,201).

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a trimethylolpropaneester-based multi-component synthesized plasticizer composition byadding benzoic acid as an aromatic acid and aliphatic mono-carboxylicacid with 3 to 10 saturated linear or branched carbon atoms totrimethylolpropane as a triply-charged alcohol so that a polyvinylchloride resin body having superior tensile strength, elongation,migration resistance, and sheet heating loss etc. can be prepared byusing it as a plasticizer during polyvinyl chloride resin processing.

In order to achieve the object, the present invention provides aplasticizer composition comprising trimethylolpropane ester shown in thefollowing Formula 1:

wherein R₁, R₂, and R₃ are a phenyl group or an alkyl group with 3 to 10and preferably 4 to 5 carbon atoms, respectively.

Furthermore, the present invention provides a polyvinyl chloride resinbody comprising the plasticizer composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described in detail as follows.

The mixture of trimethylolpropane (TMP) ester of the present inventioncomprises a) trimethylolpropane-tri-(2-ethyl hexanoate), b) benzoic acid2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, c) 2-ethylhexanoic acid2,2-bis-(benzoyloxymethyl)-butyl ester, and d) trimethylolpropane-tri-benzoate. That is, the 4 different kinds of ester in thetrimethylolpropane ester compound shown in the above Formula 1.

The trimethylolpropane ester plasticizer composition of the presentinvention, used in processing of polyvinyl chloride resin havingsuperior physical processing properties such as compatibility, migrationresistance, etc., is prepared by adding benzoic acid and 2-ethylhexanoicacid as raw materials to trimethylolpropane.

The mixture comprises 5 to 60 wt % of trimethylolpropane-tri-(2-ethylhexanoate), 20 to 70 wt % of benzoic acid2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, 5 to 50 wt % of2-ethylhexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester, and 1 to 30wt % of trimethylol propane-tri-benzoate; and more preferably comprises15 to 40 wt % of trimethylolpropane-tri-(2-ethyl hexanoate), 4.0 to 50wt % of benzoic acid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, 15to 35 wt % of 2-ethylhexanoic acid 2,2-bis-(benzoyloxymethyl)-butylester, and 1 to 10 wt % of trimethylol propane-tri-benzoate.

When the mixture of trimethylolpropane ester of the present invention isprocessed with polyvinyl chloride, the physical properties thereof areat least equal to physical properties of the prior art, and particularlysheet volatile loss and migration resistance are superior when comparedwith DEHP used as a standard plasticizer.

Trimethanolpropane ester of mono-component no multi-component, forexample in the case of ester synthesized by adding only lauric acid asan aliphatic acid with 12 carbon atoms to trimethylolpropane, isdifficult to use as a plasticizer due to its non-compatibility withpolyvinyl chloride. In the case of ester synthesized is by adding only2-ethylhexanoic acid to trimethylolpropane, it has compatibility, butmigration resistance is poor and flowing out the processed sheet surfaceis problematic.

On the other hand, in the case of a multi-component trimethylolpropaneester, different physical properties are shown depending on kinds ofalcohol and carboxylic acid used. That is, a multi-component estersynthesized by using trimethylolpropane and lauric acid and2-ethylhexanoic acids as raw materials is not compatible with polyvinylchloride resin, in the same way as a case of adding only lauric acid totrimethylolpropane for synthesis. If the ester synthesizes bysimultaneously adding 2-ethylhexanoic acid and acetic acid totrimethylolpropane, 24 hrs after the specimen production flowing theplasticizer out of the specimen becomes problematic, since compatibilityis superior but migration resistance falls.

As mentioned, with both multi-component trimethylolpropane ester andmono-component trimethanolpropane ester, selective synthesis of acid andalcohol is very important because it is hard to produce all the desiredphysical properties such as compatibility, migration resistance etc.with polyvinyl chloride resin.

Furthermore, in the case of migration resistance, generally there is aneffect on the structure of ester materials or the outside environment. Aplasticizer having a high molecular weight has excellent migrationresistance of more than a plasticizer having a low molecular weightamong the structure of ester materials.

Therefore, the multi-component trimethylolpropane ester mixtureaccording to the present invention prepares a suitable composition asaforementioned, by adding suitable acids and alcohol as raw materials,namely 2-ethylhexanoic acid-as the aliphatic acid and benzoic acid asthe aromatic acid, to trimethylolpropane.

The plasticizer composition comprising trimethylolpropane ester of thepresent invention is prepared by the following method.

In concrete terms, in order to prepare a plasticizer compositioncomprising trimethylolpropane ester comprising a) 5 to 60 wt % oftrimethylolpropane tri 2-ethylhexanoate, b) 20 to 70 wt % of benzoicacid 2,2-bis 2-ehtylhexanoyloxymethyl butyl ester, c) 5 to 50 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymethyl butyl ester, and d) 1 to30 wt % of trimethylpropane tribenzoate, i) 10 to 30 wt % oftrimethylolpropane, ii) 20 to 70 wt % of 2-ethylhexanoic acid, iii) 10to 60 wt % of benzoic acid, iv) 1 to 10 wt % of xylene, and v) 0.05 to 1wt % of tetraisopropyltitanate are added to a flask equipped with astirrer and condenser, the mixture is reacted for 4 to 20 hrs at 220°C., and un-reacted acid is removed through decompressing with a vacuumpump. The reactant is neutralized with 5 to 15 wt % of sodium hydroxideand washed, and then adsorbent is added to the reactant to remove waterby hydrating under vacuum, followed by filtering.

In the process, xylene is an entrainer, and tetraisopropyltitanate playsthe part of a catalyst.

The present invention provides a polyvinyl chloride resin body havingexcellent tensile strength, elongation, migration resistance, and sheetheating loss etc. using the trimethylolpropane ester composition as aplasticizer.

Hereinafter, the present invention is described in more detail throughthe following EXAMPLES and COMPARATIVE EXAMPLES. However, the followingEXAMPLES are only for the understanding of the present invention, andthe present invention is not limited to the following EXAMPLES.

EXAMPLES Example 1

(Preparation of Plasticizer Composition Comprising TrimethyloipropaneEster)

To a 2 l, 4-neck round flask equipped with a stirrer and a condenser,268.36 g of trimethylolpropane, 576.84 g of 2-ethylhexanoic acid, 366.39g of benzoic acid, 50 g of xylene as an entrainer material, and 2.83 gof tetraisopropyltitanate as a catalyst were added, and the reaction wasperformed for 10 hrs by raising the temperature of the mixture to 220°C.

After reaction, un-reacted acid was removed by evacuating the flask to 2mmHg with a vacuum pump at 200° C., and the flask contents wereneutralized with 5 wt % of sodium hydroxide and a washing and dryingprocess was performed, and then the trimethylolpropane ester mixture wasobtained by adding absorbent to the resultant and filtering.

(Method for Processing of Polyvinyl Chloride)

In order to measure physical properties of the trimethylolpropane estermixture obtained, the specimen was prepared to ASTM D638 standard. Thatis, 60 phr of the obtained trimethylolpropane ester plasticizer mixture,3 phr of calcium-zinc stabilizer (LTX-620S, product of KOREA DAEHYUPCHEMICAL CO., LTD), and 0.2 phr of stearic acid was mixed with polyvinylchloride resin (LS100, product of LG. CHEMICAL CO., LTD), and a 5 mmsheet was prepared with a working roll mill over 3 min at 165° C.Thereafter a press operation was performed preheating for 3 min, heatingfor 3 min, and cooling for 3 min at 185° C., and then a 1 mm sheet wasfabricated to prepare a plurality of dumbbell-shaped type C samples.

(Experiment of Physical Properties)

The specimen prepared by the method was pulled cross head speed by 500mm/min through the ASTM D638 method (That is, U.T.M as a testinstrument), and then tensile strength and elongation was measured at aplace on cutting the specimen. Tensile strength (kgf/mm²) was calculatedas load value(kgf)/thickness(mm)×width(mm), and elongation(%) wascalculated as extension/initial length×100.

Needle of hardness experimental instrument (C type) was got downperfectly, and then the hardness value was read shown after 10 sec. Thehardness was measured by the average value testing at 5 positions foreach specimen.

Sheet heating loss was calculated by measuring initial weight (Wi) tothe forth decimal place for each specimen, and then fixing the specimensin an oven at 130° C. using a clamp. Thereafter the specimen was storedfor 4 hrs or more in thermostat by taking out after 3 hrs, and thespecimen weights (Wo) were measured, and then sheet heating loss wascalculated by Equation 1 below. $\begin{matrix}{{H\quad e\quad a\quad t\quad i\quad n\quad g\quad l\quad o\quad s\quad s} = {\frac{\left( {{W\quad i} - {W\quad o}} \right)}{W\quad i} \times 100}} & \left\lbrack {{Equation}\quad 1} \right\rbrack\end{matrix}$

Migration resistance was calculated by measuring initial weight(Wi) tothe forth decimal place for each specimen, and each specimen sheet (3cm×3 cm) was placed between polystyrene (PS) plates in an oven at 80° C.and left for 48 hrs under a pressure of 1 kg. Thereafter the specimenwas stored for 4 hrs or more in thermostat by taking out at oven, andthe specimen weights (Wo) were measured, and migration resistance wascalculated by Equation 2 below. $\begin{matrix}{{M\quad i\quad g\quad r\quad a\quad t\quad i\quad o\quad n\quad r\quad a\quad t\quad e} = {\frac{\left( {{W\quad i} - {W\quad o}} \right)}{W\quad i} \times 100}} & \left\lbrack {{Equation}\quad 2} \right\rbrack\end{matrix}$

Static heat-resistance was measured using a Mathis oven. A specimen of40 cm×2 cm was introduced into the oven at 195° C., it was removed in 30mm increments at 3-minutes intervals, and appearance changes such ascolor at each interval were evaluated based on DEHP used as the standardplasticizer. Results of the physical properties measured by the methodare shown in Table 2.

Example 2

The trimethylolpropane ester and the specimen were prepared by the samemethod as in Example 1, except that materials and amounts were as shownin Table 1 below, and the results of physical property measurements areshown in Table 2 below.

The composition ratio of the ester mixture was 25.65 wt % oftrimethyloipropane tri-2-ethylhexanoate, 44.72 wt % of benzoic acid2,2-bis 2-ethylhexanoyloxymethyl butyl ester, 24.05 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymethyl butyl ester, 3.47 wt % oftrimethylolpropane tribenzoate, and 211 wt % of other components.

Example 3

The trimethylolpropane ester and the specimen were prepared by the samemethod as in Example 1, except that materials and amounts were as shownin Table 1 below, and the results of physical property measurements areshown in Table 2 below. The composition ratio of the ester mixture was34.51 wt % of trimethylolpropane tri-2-ethylhexanoate, 44.56 wt % ofbenzoic acid 2,2-bis 2-ethylhexanoyloxymethyl butyl ester, 17.52 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymethyl butyl ester, 1.38 wt % oftrimethyloipropane tribenzoate, and 2.03 wt % of other components.

Comparative Example 1

The trimethyloipropane ester and the specimen were prepared by the samemethod as in Example 1, except that the most widely used plasticizer,di-2-ethylhexylphthalate (DHEP, product of LG. CHEMICAL CO., LTD) wasused, and the measured physical property results are shown in Table 2.

Comparative Example 2

The trimethylolpropane tri-2-ethylhexanoate and the specimen wereprepared by the same method as in Example 1, except that materials andamounts were as shown in Table 1 below, and the results of physicalproperty measurements are shown in Table 2 below.

Comparative Example 3

The trimethylol propane-tri-laurate and the specimen were prepared bythe same method as in Example 1, except that materials and amounts wereas shown in Table 1 below, and the results of physical propertymeasurements are shown in Table 2 below.

Comparative Example 4

The trimethylolpropane ester mixture and the specimen were prepared bythe same method as in Example 1, except that materials and amounts wereas shown in Table 1 below, and the results of physical propertymeasurements are shown in Table 2 below.

Comparative Example 5

The trimethylolpropane ester mixture and the specimen were prepared bythe same method as in Example 1, except that materials and amounts wereas shown in Table 1 below, and the results of physical propertymeasurements are shown in Table 2 below.

TABLE 1 Example Com. Example Division (g(mole)) 1 2 3 2 3 4 5 Materialof ester Trimethylol 268.36 268.36 268.36 268.36 268.36 268.36 268.36propane (2) (2) (2) (2) (2) (2) (2) 2-ethylhexa 576.84 663.37 721.05951.80 — 634.50 — noic acid (4) (4.6) (5) (6.6) (4.4) Benzoic 366.39293.09 244.26 — — — — acid (3) (2.4) (2) Lauric — — — — 1442.2 440.70661.10 acid (7.2) (2.2) (3.3) Acetic — — — — — — 336.90 acid (3.3)Xylene 50 50 50 50 50 50 50 Tetraisopropyl- 2.83 2.39 2.90 2.85 3.612.15 3.00 titanate Comparative Example 1 used di-2-ethylhexylphthalate(DHEP, products of LG. CHEMICAL CO., LTD) as a plasticizer.

TABLE 2 Com. Com. Com. Com. Com. Example Example Example Example ExampleExample Example Example Division 1 2 3 1 2 3 4 5 Tensile 2.20 1.90 1.851.75 1.87 1.70 No No strength common common (kgf/mm²) property propertyElongation 363 350 343 378 390 400 (%) Migration 2.32 3.15 3.61 3.955.12 6.53 resistance (%) Hardness 84 82 83 78 84 80 Sheet 2.25 2.57 2.787.24 4.45 4.26 heating loss (%) Static heat- equality equality equalitystandard equality inferiority resistance

As can be seen in Tables 1 and 2, Examples 1 to 3 that were synthesizedusing trimethylolpropane, 2-ethylhexanoic acid, and benzoic acid as rawmaterials were equal in static heat-resistance, and they showed superiorphysical properties in tensile strength, migration resistance, and sheetheating loss etc. compared with di-2-ethylhexylphthalate (ComparativeExample 1) used in the standard plasticizer.

In addition, the mono-component ester synthesized by adding only2-ethylhexanoic acid to trimethylolpropane (Comparative Example 2) andthe mono-component ester synthesized by adding only lauric acid totrimethylolpropane (Comparative Example 3) had compatibility, but aproblem of bad migration resistance etc. occurred.

Furthermore, the ester synthesized by adding 2-ethylhexanoic acid andlauric acid with 12 carbon atoms as aliphatic acid to trimethylolpropane(Comparative Example 4) and the ester synthesized by adding lauric acidwith 12 carbon atoms as aliphatic acid and acetic acid totrimethylolpropane (Comparative Example 5) were difficult to use asplasticizers due to lack of compatibility with polyvinyl chloride.

As can be seen in the experimental results, when multi-componentpolyvinyl chloride resin was processed, in the case of themulti-component trimethylolpropane ester mixture as a plasticizer,namely the ester synthesized as a composition of trimethylolpropane,2-ethylhexanoic acid, and benzoic acid, a polyvinyl resin body can beprepared having excellent physical properties.

The present invention can prepare polyvinyl chloride resin havingsuperior tensile strength, elongation, migration, and sheet heating lossetc. by using the plasticizer composition.

What is claimed is:
 1. A plasticizer composition, comprising: a)trimethylolpropane-tri-2-ethyl hexanoate; b) benzoic acid2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 2-ethyl hexanoicacid 2,2-bis-(benzoyloxymethyl)-butyl ester; and d)trimethylolpropane-tri-benzoate.
 2. The composition according to claim1, wherein the composition comprises: a) 5 to 60 wt % oftrimethylolpropane-tri-2-ethyl hexanoate; b) 20 to 70 wt % of benzoicacid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 5 to 50 wt % of2-ethyl hexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester; and d) 1to 30 wt % of trimethylolpropane-tri-benzoate.
 3. The compositionaccording to claim 1, wherein the composition comprises: a) 15 to 40 wt% of trimethylolpropane-tri-2-ethyl hexanoate; b) 40 to 50 wt % ofbenzoic acid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 15 to35 wt % of 2-ethyl hexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester;and d) 1 to 10 wt % of trimethylolpropane-tri-benzoate.
 4. Thecomposition according to claim 1, wherein the composition is prepared bya method comprising steps of reacting: i) 10 to 30 wt % oftrimethylolpropane; ii) 20 to 70 wt % of 2-ethylhexanoic acid; iii) 10to 60 wt % of benzoic acid; iv) 1 to 10 wt % of xylene; and v) 0.01 to 1wt % of tetraisopropyltitanate for 4 to 20 hrs. at 220° C.
 5. Thecomposition according to claim 1, wherein the composition is prepared bya method comprising steps of reacting: i) 15 to 25 wt % oftrimethylolpropane; ii) 35 to 65 wt % of 2-ethylhexanoic acid; iii) 10to 40 wt % of benzoic acid; iv) 2 to 7 wt % of xylene; and v) 0.01 to0.7 wt % of tetraisopropyltitanate for 4 to 20 hrs. at 220° C.
 6. Apolyvinyl chloride resin body comprising: polyvinyl chloride; and thecomposition according to claim
 1. 7. A polyvinyl chloride resin bodycomprising: polyvinyl chloride; and the composition according to claim4.